Preceramic Polymers to Hafnium Carbide Ceramic Fibers and Matrices
Summary:
MATECH Global Strategic Materials (MATECH, Westlake Village, CA) has invented equipment to manufacture hafnium carbide (HfC) and hafnium carbide nitride (HfCN) ceramic fiber from preceramic polymers. Parts made with a HfC-HfC-woven fiber-reinforced matrix can withstand more heat than similar parts made with silicon carbide fiber, but at sixty percent of the density of metal-metal alloys such as rhenium-tungsten alloys. HfC composites would be useful in aerospace applications such as rocket nozzles.
Technology Description:
Hafnium carbide (HfC) is a compound with the highest known melting temperature in existence at 3890°C. In theory, a part made with HfC fiber-matrix composite would survive temperatures that would soften or melt even refractory metal-metal alloys such as rhenium-tungsten blends. HfC has about sixty percent of the density of metal alloys, so critical rocket, missile, and aerospace components made with HfC composites would be correspondingly lighter.
To date nobody had made HfC fibers from preceramic polymer. MATECH engaged in basic and applied research and developed over one dozen melt-spinnable HfC preceramic polymers. As with regular organic polymers, preceramic polymer can be melted, spun, and dissolved into common solvents. MATECH starts with raw materials and synthesizes monomers and polymers in its laboratory. A solid preceramic polymer mass is placed into a piston chamber and then heated, pressurized, and forced through a fine orifice, akin to liquid being squirted out of a syringe. A strand or filament more than 30 kilometers long can be produced continuously and wound on one spool. In the laboratory, the company equipment can produce anywhere between 1 and 30 fiber strands at the same time. A pilot plant would produce between 100 and 500 filaments simultaneously.
Research also proceeds into the process by which fibers are cured or heated in a non-oxidizing atmosphere and then made into useful ceramic parts. When cured, a matrix transforms from a thermoplastic to a thermoset and then is locked into shape. Curing can occur by a number of mechanisms including thermally, by photo-curing, chemically, or even via radiation by electron beams.
MDA Origins:
MDA awarded a Phase I SBIR contract to MATECH in 2002 to investigate the basic feasibility of making HfC fiber from preceramic polymers for rocket nozzles and engine combustion liners. The results were successful enough to prompt MDA to award the company a follow-on Phase II contract to study the strength, creep resistance, stoichiometry, and optimization and quality of parts made with HfC-HfC-woven fiber-reinforced matrix.
Spinoff Applications:
Because HfC composite is a high-temperature-resistant and ''high Z'' material, its applications are in the aerospace industry. One possibility is zero-erosion ablative liners for combustion chambers used in rocket motors. Leading-edge surfaces on vehicles entering an atmosphere also endure the kind of ultra-high temperatures that HfC composite can withstand without degrading; aerospace engineers will be able to work with the entirely new compound to improve hypersonic craft performance. Hafnium can absorb large quantities of radiation and possibly be useful in radiation shielding for long-duration space missions.
Commercialization:
MATECH has a memorandum of understanding with a well-established U.S. aerospace materials company to transition mature technologies from development to manufacturing. As of 2004, MATECH is still doing fundamental applied research on manufacturing HfC polymers, fibers, and fiber matrices. In 2004 the company filed a process patent and was preparing to file an application patent as well.
Company Profile:
MATECH was founded in 1989 and is a privately held corporation. It has a product line that is unrelated to aerospace high temperature ceramics but nevertheless contributes to annual revenues in excess of $2 million. Roughly 60 to 70 percent of its revenue is derived from government contracts. The company employs 16 full-time employees, up from five in 2003, and anticipates continued expansion at the same rate for the immediate future. Although it currently occupies a facility of only 6,500 square feet, it anticipates expanding the facility as well, to accommodate continued growth. The company intends to remain in California to stay close to its customer base and existing partnerships.
Contact Information:
Dr. Edward J. A. Pope
MATECH Global Strategic Materials
31304 Via Colinas, Suite 102
Westlake Village, CA 91362-3901
Tel: (818) 991-8500
Fax: (818) 991-4134
email: ed@matechgsm.com
web: www.matechgsm.com
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